Manufacture of hydroxydiphenyls



Patented Oct. 30, 1934 PATENT or ies MANUFACTURE OF HYDROXYDIPHENYLS Joe E. Moose, Anniston, A1a., assignor to Swann Research, Incorporated, a corporation of Alabama No Drawing. Application March 16, 1932, Serial No. 599,339

12 Claims.

This invention relates to a process for ducing hydroxydiphenyls.

One object of this invention is the provision of a process for producing meta hydroxydiphenyl. Another object is the provision of a process for producing hydroxydiphenyls in good yield. A still further object is the provision of a process by which halogenated diphenyls may be hydrolyzed without the production of considerable amounts of isomeric hydroxy-diphenyls.

To the accomplishment of the foregoing and related ends, the invention, then, consists in the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth but a few of the various ways in which the principle of the invention may be used.

In accordance with the invention one or more mono halogenated derivatives of diphenyl or a halogenated diphenyl hydrocarbon is heated with an aqueous alkaline body such as aqueous caustic soda or sodium carbonate or the equivalent potassium compounds.

According to the prior art (German Pat. No. 249,939 (1912); British Patent 9450 (1913)) it is to be expected that when a halogenated aromatic hydrocarbon or derivative thereof is hydrolyzed with an alkaline body under pressure in a copper vessel that the hydroxy body obtained will correspond structurally to the halogenated body originally employed. I have, however, found this not to be the case when a halogenated diphenyl is employed. In such a case, when employing a mono halogenated diphenyl, say the 2 or 4 chlorodiphenyl, I find appreciable quantities of 3 hydroxydiphenyl to be formed.

My invention may, therefore, be said to embrace the simultaneous production of B-hydroxydiphenyl together with 2- and e-hydroxydiphenyl.

The reactions may be carried out in a completely copper lined autoclave in intermittent manner, or they may be carried out continuously in a copper lined tubular converter, such, for example, as that described by Aylsworth in U. S.

Patent No. 1,213,142 or by Griswold in U. S. Patent No. 1,602,766 or 1,833,485.

When operating in a continuous fashion it is customary, when producing phenol, according to the above patents to make a liquid mixture of the halogenated benzene and the caustic soda which liquid mixture is maintained in the state of an emulsion by means of stirring devices. By thus maintaining a uniform emulsion the pumps are enabled to force the emulsified mixture dipro rectly into the autoclave or tubular converter in convenient manner.

I have, however, found that considerable difiiculty is encountered when pumping a similar emulsion of the mono-chloro diphenyls since the freezing point of the 2-chloro isomer is 34 C. and that of the i-chloro isomer is 755 C. making it necessary to maintain the emulsified mixture as well as the pumps and conveying lines at a relative high temperature in order to keep both parts of the emulsion in the liquid phase and avoid stoppage of the flow. I have now been able to overcome this difficulty by mixing together various proportions of 2 and l-chloro diphenyl taking advantage of the lowered freezing point of this mixture.

The following table illustrates the freezing points to be obtained with mixtures of 2 and 4 chloro-diphenyl:-

Composition of mixture Freezing point i-chlor and 50% 2-ch1orodiphenyl...

By employing mixtures of the above compounds within the range indicated, I am enabled to utilize temperatures below 34 C. at which a completely liquid emulsion may be made Without the necessity of employing excessively high temperatures either for the pumps, conveying lines, or the emulsion itself.

The above low freezing compositions are also of value if one resorts to the practice of introducing the caustic soda solution and the chlorodiphenyl by separate pumps. By employing a mixture as above set out, danger of stoppage can be avoided without resorting to high temperature heating.

As an example of several means for carrying out my invention, I cite the following specific examples.

Through a continuous tubular copper lined converter, provided with heating means, pump a liquid mixture or emulsion of 188.6 parts (1 mol.) of Z-chlorodiphenyl, m. p. 34 C. and 100 parts (2.5 mols.) of caustic soda, (NaOH) in solution, the latter being of 15% strength. The temperature of the tubes of the converter should be maintained in the neighborhood of 365 C. In such a converter iron should be kept from contact with the solution at the reacting temperature. The

pressure to be maintained by means of the pump is approximately 3,500 lbs. per sq. in. or somewhat above the vapor pressure of the solution at that temperature. The rate of pumping of the emulsion should be such as will subject the reaction mixture to the above temperature fora period of say 40 minutes, which time may, however, be somewhat varied in order to permit the reacting substances to attain chemical equilibrium, which will vary somewhat with the temperature. The reaction products are continuously discharged in known manner, the hydroxydiphenyls being regenerated from the corresponding phenates by acidification. Separation may be accomplished by distillation or by fractional crystallization. The yield of 3-hydroxydiphenyl will be found to be in the neighborhood of 35-50% of the hydroxydiphenyls formed, the remainder being Z-hydroxydiphenyl.

In analogous manner I may hydrolyze a mixture of ortho and para hydroxydiphenyl. When employing a mixture of percent of 2-ch1or and 20 percent of l-chlorodiphenyl the mixture is main tained as a liquid-emulsion at temperatures above 15.5 C. As a result of the hydrolysis of this mixture I obtain a yield of 35 to 50% of 3-hydroxydiphenyl, the remainder being almost wholly 2- hydroxydiphenyl.

While I have described several embodiments of my invention, it Will be apparent to those skilled in the art, that it is not so limited, but that it is susceptible of various changes and modifications without departing from the spirit thereof, and I desire that only such limitations shall be placed thereupon as may be imposed by the prior art or as are specifically set forth in the appended claims.

I claim:

1. Process for producing a mixture of hydroxydiphenyls comprising hydrolyzing in the liquid phase and at a temperature sufiicient to bring about reaction, a chlorinated diphenyl included within the group; 2 chlorodiphenyl, 4 chlorodiphenyl, in the presence of an alkali metal hydroxide and copper.

2. Process for producing a mixture of hy droxydiphenyls, said mixture containing'B-hydroxydiphenyl comprising hydrolyzing in the liquid phase and at a temperature sufiicient to bring about reaction, a chlorinated diphenyl included within the group; 2 chlorodiphenyl, 4 chlorodiphenyl, in the presence of an alkali metal hydroxide and copper.

3. Process for producing a mixture of hydroxydiphenyls, said mixture containing 3-hydroxydiphenyl, comprising heating at a temperature sufficient to effect hydrolysis, a mono-chlorinated diphenyl included within the group; 2 chlorodiphenyl, 4 chlorodiphenyl with dilute aqueous caustic soda in the presence of copper.

4. In the process for producing 3-hydroxydiphenyl by liquid phase hydrolysis of a monochlorinated diphenyl which does not correspond structurally with said B-hydroxydiphenyl, the step comprising causing said hydrolysis to proceed in the presence of an alkali metal hydroxide and metallic copper.

5. Process for producing a mixture of hydroxydiphenyls, said mixture containing 3-hydroxydiphenyl, comprising hydrolyzing in the liquid phase at a temperature of about 365 C. mono-chlorinated diphenyls, said mono-chlorinated diphenyls comprising a chlorinated diphenyl included within the group; 2 chlorodiphenyl, 4 chlorodiphenyl, in the presence of an alkali metal hydroxide and metallic copper.

6. In a process for producing mono hydroxydiphenyls by liquid-phase hydrolysis with aqueous caustic soda solutions the step of hydrolyzing a mixture of 2 and 4 chlorodiphenyl.

"7. In a process for producing mono hydroxydiphenyl by liquid-phase hydrolysis with aqueous caustic soda solutions the step of hydrolyzing a mixture of 2 and 4 chlorodiphenyl, said mixture having a melting point below 34 C.

8. Process for producing a mixture of hydroxydiphenyl hydrocarbons comprising hydrolyzing in the liquid phase by means of aqueous caustic soda a chlorinated diphenyl hydrocarbon in the presence of copper.

9. In the process of hydrolyzing a mono halogenated diphenyl hydrocarbon, the step of forming an isomeric hydroxy derivative thereof by effecting such hydrolysis in the liquid phase by means of aqueous caustic soda in the presence of metallic copper. v

10. In the process of hydrolyzing a mono halogenated diphenyl hydrocarbon, the step of forming an isomeric hydroxy derivative thereof by effecting such hydrolysis by means of an aqueous solution of caustic soda in the presence of copper and at a temperature effective to form such hydroxy derivative.

' 11. Inthe process of hydrolyzing a monohalogenated diphenyl, the step of forming an isomeric hydroxydiphenyl by effecting such hydrolysis in the liquid phase by means of aqueous caustic soda solution in the presence of metallic copper and at a temperature and pressure eifective to bring about such hydrolysis.

12. In the process of hydrolyzing a monochlorinated diphenyl, the step of forming an isomeric hydroxydiphenyl by effecting the hydrolysis in the liquid phase by means of aqueous caustic soda solution in the presence of metallic copper and at a temperature in the neighborhood of 365 C.

- JOE E. MOOSE. 

